Referral and treatment patterns in pancreatic acinar cell carcinoma: A regional population-level analysis.

BACKGROUND: Pancreatic acinar cell carcinoma (PACC) is a rare exocrine tumor of the pancreas. We evaluated the effect disease stage, surgical intervention, and institutional volume status plays in survival. METHODS: We queried the Oregon State Cancer Registry for patients with PACC from 1997 to 2018. Treatment and referral patterns were analyzed, and overall survival (OS) was evaluated with Kaplan-Meier and Cox-proportional hazard analysis. RESULTS: 43 patients were identified. Median OS was 33.1 and 7.1 months in those with locoregional and metastatic disease respectively (p â€‹= â€‹0.008). Surgical intervention was associated with improved OS (hazard ratio 0.28, p â€‹< â€‹0.0001). High volume center (HVC) care trended towards improving OS. While the majority of cases were diagnosed at low volume centers (74%), referral to HVCs was rare (n â€‹= â€‹4) and limited to advanced (stage III/IV) disease. CONCLUSION: Stage and surgical resection influence survival outcomes in PACC, more data is needed to delineate the impact of institutional volume status.

γ' fibrinogen levels as a biomarker of COVID-19 respiratory disease severity.

Coronavirus disease 2019 (COVID-19) is characterized by a pro-inflammatory state associated with organ failure, thrombosis, and death. We investigated a novel inflammatory biomarker, γ' fibrinogen (GPF), in 103 hospitalized patients with COVID-19 and 19 healthy controls. We found significant associations between GPF levels and the severity of COVID-19 as judged by blood oxygen saturation (SpO2). The mean level of GPF in the patients with COVID-19 was significantly higher than in controls (69.8 (95 % CI 64.8-74.8) mg/dL compared with 36.9 (95 % CI 31.4-42.4) mg/dL, p < 0.0001), whereas C-reactive protein (CRP), lactate dehydrogenase (LDH), and total fibrinogen levels were not significantly different between groups. Mean GPF levels were significantly highest in patients with severe COVID-19 (SpO2 ≤ 93 %, GPF 75.2 (95 % CI 68.7-81.8) mg/dL), compared to mild/moderate COVID-19 (SpO2 > 93 %, GPF 62.5 (95 % CI 55.0-70.0) mg/dL, p = 0.01, AUC of 0.68, 95 % CI 0.57-0.78; Youden's index cutpoint 62.9 mg/dL, sensitivity 0.64, specificity 0.63). In contrast, CRP, interleukin-6, ferritin, LDH, D-dimers, and total fibrinogen had weaker associations with COVID-19 disease severity (all ROC curves with lower AUCs). Thus, GPF may be a useful inflammatory marker of COVID-19 respiratory disease severity.

High-volume centers are associated with higher receipt of combined therapy in stage III pancreatic cancer.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at a locally advanced stage with vascular involvement which was previously viewed as a contraindication to resection. However, high-volume centers are increasingly capable of resecting complex tumors. We aimed to explore patterns of treatment that are uncharacterized on a population level. METHODS: A statewide registry was queried from 2003 to 2018 for stage III PDAC. Stepwise logistic regression and Kaplan-Meier were used for statistical analysis. RESULTS: We identified 424 eligible patients. 348 (82%) received chemotherapy, 17 (4.0%) received resection, and 59 (13.9%) received both; median survival was 10.7, 8.7, and 22.7 months, respectively (P < 0.001). High-volume centers (≥20 cases per year; OR 5.40 [95% CI: 2.76, 10.58], P < 0.001) and later year of diagnosis (OR 1.12/year [95% CI: 1.04, 1.20], P = 0.004) were associated with higher odds of receiving combined therapy. CONCLUSION: PDAC patients with vascular involvement who receive both systemic chemotherapy and surgical resection have improved overall survival. High-volume centers are independently associated with higher odds of receiving combined systemic therapy and surgical resection.

Socioeconomic and Geographic Disparities in the Referral and Treatment of Pancreatic Cancer at High-Volume Centers.

Importance: Treatment at high-volume centers (HVCs) has been associated with improved overall survival (OS) in patients with pancreatic ductal adenocarcinoma (PDAC); however, it is unclear how patterns of referral affect these findings. Objective: To understand the relative contributions of treatment site and selection bias in driving differences in outcomes in patients with PDAC and to characterize socioeconomic factors associated with referral to HVCs. Design, Setting, Participants: A population-based retrospective review of the Oregon State Cancer Registry was performed from 1997 to 2019 with a median 4.3 months of follow-up. Study participants were all patients diagnosed with PDAC in Oregon from 1997 to 2018 (n = 8026). Exposures: The primary exposures studied were diagnosis and treatment at HVCs (20 or more pancreatectomies for PDAC per year), low-volume centers ([LVCs] less than 20 per year), or both. Main Outcomes and Measures: OS and treatment patterns (eg, receipt of chemotherapy and primary site surgery) were evaluated with Kaplan-Meier analysis and logistic regression, respectively. Results: Eight thousand twenty-six patients (male, 4142 [52%]; mean age, 71 years) were identified (n = 3419 locoregional, n = 4607 metastatic). Patients receiving first-course treatment at a combination of HVCs and LVCs demonstrated improved median OS for locoregional and metastatic disease (16.6 [95% CI, 15.3-17.9] and 6.1 [95% CI, 4.9-7.3] months, respectively) vs patients receiving HVC only (11.5 [95% CI, 10.7-12.3] and 3.9 [95% CI, 3.5-4.3] months, respectively) or LVC-only treatment (8.2 [95% CI, 7.7-8.7] and 2.1 [95% CI, 1.9-2.3] months, respectively; all P < .001). No differences existed in disease burden by volume status of diagnosing institution. When stratifying by site of diagnosis, HVC-associated improvements in median OS were smaller (locoregional: 10.4 [95% CI, 9.5-11.2] vs 9.9 [95% CI, 9.4-10.4] months; P = .03; metastatic: 3.6 vs 2.7 months, P < .001) than when stratifying by the volume status of treating centers, indicating selection bias during referral. A total of 94% (n = 1103) of patients diagnosed at an HVC received HVC treatment vs 18% (n = 985) of LVC diagnoses. Among patients diagnosed at LVCs, later year of diagnosis and higher estimated income were independently associated with higher odds of subsequent HVC treatment, while older age, metastatic disease, and farther distance from HVC were independently associated with lower odds. Conclusions and Relevance: LVC-to-HVC referrals for PDAC experienced improved OS vs HVC- or LVC-only care. While disease-related features prompting referral may partially account for this finding, socioeconomic and geographic disparities in referral worsen OS for disadvantaged patients. Measures to improve access to HVCs are encouraged.

Hospital Care for Adult Patients with Congenital Heart Diseases.

OBJECTIVE: The ideal type of hospital to care for adult congenital heart disease (ACHD) patients is not well known. Hospital competitiveness, clinical volume and market structure can influence clinical outcomes. We sought to understand how hospital competitiveness affects clinical outcomes in ACHD patients in the era prior to the Adult Congenital Heart Association accreditation program. METHODS: Patient discharges with ACHD diagnosis codes were filtered between 2006-2011 from an all-payer inpatient healthcare database. Hospital-level data was linked to market structure patient flow. A common measure of market concentration used to determine market competitiveness-the Herfindahl-Hirschman Index (HHI)-was stratified into: more competitive (HHI ≤25th percentile), moderately competitive (HHI 25th to <75th percentile), and less competitive (HHI ≥75th percentile) hospital. Any complication, home discharge and mortality were analyzed with clustered mixed effects logistic regression. The combined impact of HHI and any complication on mortality by interaction was assessed. RESULTS: A total of 67,434 patient discharges were isolated. More competitive hospitals discharged the least number of patients (N = 15,270, 22.6%) versus moderately competitive (N = 36,244, 53.7%) and less competitive (N = 15,920, 23.6%) hospitals. The adjusted odds of any complication or home discharge were not associated with hospital competitiveness strata. Compared to more competitive hospitals, mortality at moderately competitive hospitals (Adjusted Odds Ratio (AOR) 0.79, 95% CI: 0.66-0.94) and less competitive hospitals (AOR 0.79, 95% CI: 0.63-0.98) were lower (p = 0.025). Age, race, elective admission, transfer status, and payer mix were all significantly associated with adjusted odds of any complication, home discharge and mortality (p ≤ 0.05). Having any complication independently increased the adjusted odds of mortality more than 6-fold (p < 0.001), and this trend was independent of HHI strata. Failure to rescue an ACHD patient from mortality after having any complication is highest at less competitive hospitals. Sensitivity analysis which excluded the transfer status variable, showed that any complication (p = 0.047) and mortality (p = 0.01) were independently associated with HHI strata. CONCLUSIONS: Whether lower competition allow hospitals to focus more on quality of care is unknown. Hospital competitiveness and outcome seem to have an inverse trend relationship among ACHD patients. Since medical care is frequently provided away from the home area, hospital selection is an important issue for ACHD patients. Further research is needed to determine why competitiveness is linked to surgical outcomes in this population.

Gamma' fibrinogen levels as a biomarker of COVID-19 respiratory disease severity.

Coronavirus disease 2019 (COVID-19) is characterized by a pro-inflammatory state associated with organ failure, thrombosis, and death. We investigated a novel inflammatory biomarker, γ' fibrinogen (GPF), in 103 hospitalized patients with COVID-19 and 19 healthy controls. We found significant associations between GPF levels and the severity of COVID-19 as judged by blood oxygen saturation (SpO 2 ). The mean level of GPF in the patients with COVID-19 was significantly higher than in controls (69.8 (95% CI 64.8-74.8) mg/dL compared with 36.9 (95% CI 31.4-42.4) mg/dL, p < 0.0001), whereas C-reactive protein (CRP), lactate dehydrogenase (LDH), and total fibrinogen levels were not significantly different between groups. Mean GPF levels were significantly highest in patients with severe COVID-19 (SpO 2 ≤ 93%, GPF 75.2 (95% CI 68.7-81.8) mg/dL), compared to mild/moderate COVID-19 (SpO 2 > 93%, GPF 62.5 (95% CI 55.0-70.0) mg/dL, p = 0.01, AUC of 0.68, 95% CI 0.57-0.78; Youden's index cutpoint 62.9 mg/dL, sensitivity 0.64, specificity 0.63). In contrast, CRP, interleukin-6, ferritin, LDH, D-dimers, and total fibrinogen had weaker associations with COVID-19 disease severity (all ROC curves with lower AUCs). Thus, GPF may be a useful inflammatory marker of COVID-19 respiratory disease severity.

Marrow Stimulation Has Relatively Inferior Patient-Reported Outcomes in Cartilage Restoration Surgery of the Knee: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

BACKGROUND: Multiple cartilage repair techniques are available for chondral defects in the knee. Optimal treatment is controversial. PURPOSE: To evaluate change from baseline in the 5 Knee injury and Osteoarthritis Outcome Score (KOOS) subscales among different cartilage repair techniques of the knee. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 1A. METHODS: Medline and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched for randomized controlled trials with minimum 1 year follow-up reporting change from baseline KOOS (delta KOOS) subscale values. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. A meta-analysis was performed on the following surgery types: microfracture (Mfx); augmented microfracture techniques (Mfx+Augment); and culture-based therapies, including autologous chondrocyte implantation (ACI) and matrix-assisted autologous chondrocyte implantation (MACI). A random-effects metaregression model was used. RESULTS: A total of 14 randomized trials with a total of 775 patients were included. The KOOS Sport and Recreation (Sport) and KOOS Quality of Life (QOL) were the 2 most responsive subscales after operative intervention. Outcomes from Mfx and Mfx+Augment were not different in any of the 5 KOOS subscales (minimum P > .3). The mean delta KOOS Sport after ACI/MACI was 9.9 points greater than after Mfx (P = .021) and 11.7 points greater than after Mfx+Augment (P = .027). Longer follow-up time correlated with greater delta KOOS Sport (P = .028). Larger body mass index led to greater delta KOOS QOL (P = .045). Larger cartilage defect size correlated with greater delta KOOS Pain and KOOS Activities of Daily Living scores (P = .023 and P = .002, respectively). CONCLUSION: The KOOS Sport and QOL were the most responsive subscales after cartilage restoration surgery of the knee. Culture-based therapies (ACI/MACI) led to clinically relevant improvements in the KOOS Sport score compared with marrow stimulation and may be a more appropriate treatment in younger and more active individuals. There were no benefits to Mfx+Augment over Mfx alone in any of the KOOS subscales.

Disagreement in Readmission Rates After Total Hip and Knee Arthroplasty Across Data Sets.

BACKGROUND: In 2014, the Affordable Care Act Hospital Readmissions Reduction Program began penalizing hospitals for excessive readmission rates 30 days after total hip arthroplasty (THA) and total knee arthroplasty (TKA). Various data sets with nonstandardized validation processes report readmission data, which may provide conflicting outcome values for the same patient populations. METHODS: We queried 4 separate data sets: the American Joint Replacement Registry, Centers for Medicare and Medicaid Services billing data, the Vizient data set, and an advanced analytics integration (Cognos) report from our electronic medical record. We identified 2763 patients who underwent primary TKA and THA at a single academic medical center from June 2016 to June 2019. We then matched 613 surgery encounters in all 4 databases. Our primary outcome metric was 30-day readmissions. Fleiss' Kappa was used to measure agreement among the different data sets. RESULTS: Of the 613 THA and TKA patients, there were 45 (7.3%) readmissions noted. Data collected from the Centers for Medicare and Medicaid Services flagged 41 (6.7%) readmissions, Vizient flagged 11 (1.8%) readmissions, and the American Joint Replacement Registry and Cognos report both flagged 6 (0.98%) readmissions each. None of the readmissions were identified by all 4 data sets. There was significant disagreement among data sets using Fleiss' Kappa (kappa = -0.1318, P = .03). CONCLUSION: There is disagreement in readmission rates in databases receiving the same patient data after THA and TKA. Care must be taken to establish standard validation processes and reporting methods and scrutiny applied when interpreting readmission rates from various data sets.

Directional Reflectivity of the Ellipsoid Zone in Dry Age-Related Macular Degeneration.

BACKGROUND AND OBJECTIVE: Ellipsoid zone (EZ) reflectivity on optical coherence tomography (OCT) is affected by the orientation of the scanning beam. The authors sought to determine how directional reflectivity changes in dry age-related macular degeneration (AMD). PATIENTS AND METHODS: Retrospective image analysis included 17 control and 20 dry AMD subjects. Directional OCT (D-OCT) was performed using multiple displaced pupil entrance positions. EZ pixel values and apparent incidence angles were measured. RESULTS: EZ reflectivity decreased in off-axis scans in controls (P < .001), AMD areas between drusen (P < .001), and AMD areas overlying drusen (P < .001). The magnitude of decrement in EZ reflectivity was significantly higher when incidence angles exceeded 10° in controls than in AMD areas between drusen (P = .024). CONCLUSION: EZ reflectivity in dry AMD may vary by incident angle of light less than in controls, possibly indicating alteration of photoreceptor orientation or integrity. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:145-152.].

Spinal anesthesia in a designated block bay for total joint arthroplasty: improving operating room efficiency.

BACKGROUND: Creating highly efficient operating room (OR) protocols for total joint arthroplasty (TJA) is a challenging and multifactorial process. We evaluated whether spinal anesthesia in a designated block bay (BBSA) would reduce time to incision, improve first case start time and decrease conversion to general anesthesia (GA). METHODS: Retrospective cohort study on the first 86 TJA cases with BBSA from April to December 2018, compared with 344 TJA cases with spinal anesthesia performed in the OR (ORSA) during the same period. All TJA cases were included if the anesthetic plan was for spinal anesthesia. Patients were excluded if circumstances delayed start time or time to incision (advanced vascular access, pacemaker interrogation, surgeon availability). Data were extracted and analyzed via a linear mixed effects model to compare time to incision, via a Wilcoxon rank-sum test to compare first case start time, and via a Fisher's exact test to compare conversion to GA between the groups. RESULTS: In the mixed effect model, the BBSA group time to incision was 5.37 min less than the ORSA group (p=0.018). The BBSA group had improved median first case start time (30.0 min) versus the ORSA group (40.5 min, p<0.0001). There was lower conversion to GA 2/86 (2.33%) in the BBSA group versus 36/344 (10.47%) in the ORSA group (p=0.018). No serious adverse events were noted in either group. CONCLUSIONS: BBSA had limited impact on time to incision for TJA, with a small decrease for single OR days and no improvement on OR days with two rooms. BBSA was associated with improved first case start time and decreased rate of conversion to GA. Further research is needed to identify how BBSA affects the efficiency of TJA.

Sex Differences in the Effect of Nucleus Accumbens Volume on Adolescent Drinking: The Mediating Role of Sensation Seeking in the NCANDA Sample.

OBJECTIVE: In adolescence, sensation seeking is associated with earlier onset of alcohol use, which is a risk factor for a variety of negative consequences later in life. Individual differences in sensation seeking are related to brain function in the nucleus accumbens (NAcc), a brain region that undergoes considerable structural development during adolescence. Therefore, the goal of this study was to determine whether NAcc volume in alcohol-naive adolescents was associated with future sensation seeking and alcohol use and whether these associations differed by sex. METHOD: High-resolution magnetic resonance imaging was used to measure NAcc volume at baseline in 514 alcohol-naive adolescents (50.2% female) from the National Consortium on Alcohol & Neurodevelopment in Adolescence study. Direct effects of NAcc volume on adolescent drinking 2 years after baseline, and indirect effects mediated through sensation seeking 1 year after baseline, were assessed. RESULTS: An indirect effect of NAcc volume on subsequent drinking through sensation seeking was significant for males, but not females. This effect was driven by a positive association between NAcc volume and sensation seeking observed in male, but not female, participants. A direct effect of NAcc volume on subsequent alcohol use was detected in females, but not males. In females, no association between NAcc volume and sensation seeking was detected, but NAcc volume was positively associated with future alcohol use. CONCLUSIONS: These findings suggest that delayed structural maturation of the NAcc may be a risk factor for alcohol use in adolescence; however, the mechanism by which the structure of the NAcc confers risk differs by sex.

Do hardened femoral heads reduce blood metal ion concentrations after hip resurfacing?

BACKGROUND: Elevated cobalt and chromium ion concentrations have been associated with the use of metal-on-metal bearings in hip arthroplasty. The use of a differential hardness bearing may reduce metal particle release. The aim of our study was to compare circulating cobalt (Co) and chromium (Cr) ion levels between patients treated with a standard all 'as-cast' heat treated bearing and a differential hardness bearing. MATERIALS AND METHODS: One hundred and thirty-two patients implanted with unilateral hip resurfacing arthroplasties and having had blood metal ion studies performed between one and six years after surgery were retrospectively selected. There were 73 patients in the standard all 'as cast' heat treated bearing group (group 1) and 59 in the differential hardness bearing group (group 2). RESULTS: Clinical and quality of life scores were comparable between groups. The median Co in group 1 was 1.01 µg/L and 1.23 µg/L in group 2 (p = 0.0566). The median Cr in group 1 was 1.60 µg/L and 1.34 µg/L in group 2 (p = 0.0505). CONCLUSION: Compared with conventional heat-treated CoCr bearings, differential hardness metal-on metal bearings do not confirm in vivo the hopes of a substantial reduction in circulating metal ions concentrations suggested by in vitro wear studies.

Does femoral neck to cup impingement affect metal ion levels in hip resurfacing?

BACKGROUND: Impingement of the femoral neck with the acetabular component after metal-on-metal hip resurfacing arthroplasty (HRA) is a possible cause of edge loading and accelerated bearing wear. No attempt has been made to correlate radiographic impingement signs and blood metal ion levels. QUESTIONS/PURPOSES: We (1) compared serum cobalt (CoS) and chromium (CrS) concentrations between patients with and without radiographic impingement signs treated with unilateral HRA, (2) determined whether divot depth on the femoral neck correlated with CoS and CrS, and (3) assessed the predictive value of radiographic impingement signs for high levels of CoS and CrS. METHODS: A retrospective radiographic review of 141 patients with CoS and CrS analyses yielded 21 patients with and 120 without radiographic impingement signs (controls). Radiographic measurements included divot depth and orientation of the acetabular component to compute the contact patch to rim distance, a measure of functional head coverage. We defined a patient as having radiographic impingement signs if a remodeling of the femoral neck cortex showed a depression matching the predicted path of an impinging acetabular component. CoS and CrS were analyzed by inductively coupled plasma mass spectrometry and the radiographs were taken within 12 months of the last blood draw. RESULTS: Median CoS and CrS were greater in the impingement group than in controls in patients with less than 10-mm contact patch to rim distances. Divot depth did not correlate with CoS or CrS. In predicting elevated ion levels (≥ 7 µg/L), the presence of a radiographic impingement sign showed a sensitivity of 50% for CoS and 33% for CrS and a specificity of 87% for both CoS and CrS. CONCLUSIONS: Radiographic impingement signs influenced CoS and CrS only when the functional head coverage was insufficient due to poor socket positioning. Radiographic impingement signs alone were not a good predictor of elevated metal ion levels.

Metal ion levels in total hip arthroplasty versus hip resurfacing.

Recent studies suggest that the tapered interface between stem and femoral head may be a substantial source of cobalt and chromium ion release after metal-on-metal (MOM) total hip arthroplasty (THA). This study compared patient ion levels after MOM hip resurfacing (HR) and MOM THA performed with identical acetabular components. 110 HRs were compared with 22 THAs. All had well-oriented components, unilateral implants, and serum ion studies beyond one year post-operatively. The HR group's median cobalt value was 1.11 µg/L vs. 2.86 µg/L for the THA patients. The HR group's median chromium value was 1.49 µg/L vs. 2.94 µg/L for THA. Significantly higher THA ion levels suggest a source of ions other than the MOM bearing itself.

Childhood development after maternal metal-on-metal hip resurfacing.

Metal-on-metal (MoM) hip resurfacing has been used in many young, active patients, including women of childbearing age. While ion levels have been measured in mothers with MoM hip resurfacing and their babies, little is known about how these ions affect child development. Out of 1300, MoM hip resurfacing surgeries, we had 48 women of childbearing age (defined as 40 years of age or younger at the time of surgery). These women were contacted to see if they had had pregnancies after their surgery, and those who had were sent surveys asking about their pregnancies and the development of their children. Eleven women reported pregnancies, and eight returned the surveys. There were no significant differences between women with pregnancies and those without pregnancies in any demographic or clinical measures. From the eight women who completed surveys, there were seventeen pregnancies resulting in fourteen births. There were complications in three of the births resulting in two premature births, but no children were born with birth defects. Overall, the children appear to be developing normally. Based on this unique data, we do not feel that MoM hip resurfacing is contraindicated for women of childbearing age, but power analyses show that we cannot draw conclusive results from our sample. We recommend that other groups publish their own data to allow us to generate sufficient sample sizes to draw meaningful conclusions.

The results of metal-on-metal hip resurfacing in patients under 30 years of age.

Degenerative hip conditions most commonly affect older patients. However, many cases occur in younger patients. Total hip arthroplasty is the conventional approach; however, hip resurfacing is a viable option. Fifty-three metal-on-metal resurfacings in 46 patients under age 30 were performed. Patients had a variety of etiologies, and were followed clinically and radiographically with mean follow-up of 98.2 months. Clinical scores and x-rays were compared pre-operatively and post-operatively. The last follow-up SF-12 and UCLA scores significantly improved post-operatively (P<0.0001). Range of motion scores also improved (P<0.001), and the mean Harris Hip Score was 88. There were 6 revisions. The Kaplan-Meier survivorship estimate at 8 years was 95%. Metal-on-metal hip resurfacing appears to be an effective procedure for younger patients. Longer-term data are needed for confirmation.

Do ion concentrations after metal-on-metal hip resurfacing increase over time? A prospective study.

Thirteen male and five female patients received a Conserve Plus hip resurfacing and prospectively provided blood samples to measure cobalt and chromium levels for up to 11 years. Trends in metal levels over time in unilateral and bilateral patients were studied. A multi-variate regression model was used to account for potential covariates. For unilaterals over all time intervals, the median Serum Cobalt level (CoS) was 1.06 µg/L, while the median Serum Chromium level (CrS) was 1.58 µg/L. For bilaterals, the median post operative CoS was 2.80 µg/L, while the median CrS was 5.80 µg/L. Metal levels increased within the first year then decreased and stabilized. These results show that serum metal levels in well-functioning implants can be low and do not increase with time.

Contact patch to rim distance predicts metal ion levels in hip resurfacing.

BACKGROUND: Component design, size, acetabular orientation, patient gender, and activity level have been suggested as factors leading to elevated metal ion concentrations after-on-metal hip resurfacing arthroplasty (MMHRA). The calculation of the contact patch to rim (CPR) distance integrates component size, design, and acetabular orientation and may be a good predictor of elevated metal ion levels. QUESTIONS/PURPOSES: We evaluated the effects and the predictive value of the CPR distance on serum cobalt (CoS) and chromium (CrS) ion levels. METHODS: We retrospectively studied 182 patients with Conserve Plus MMHRAs at a minimum of 12 months after surgery (median, 57 months; range, 12-165 months). CoS and CrS levels were analyzed using inductively-coupled plasma mass spectrometry. Multiple logistic regression was performed to determine which if any of the factors related to serum ion levels. RESULTS: Patients with CPR distances of 10 mm or less had a 37-fold increased risk of having elevated CoS of 7 µg/L or higher. Similarly, these patients had an 11-fold increased risk of having elevated CrS of 7 µg/L or higher. Sex and University of California Los Angeles activity scores did not influence the postoperative CoS and CrS levels. The negative predictive value for CPR distance less than 10 mm was 99.3% for CoS greater than 7 µg/L and 98.0% for CrS greater than 7 µg/L. CONCLUSIONS: Our observations suggest the CPR distance would be a useful indicator to determine which patients are at risk for elevated ion levels. Patients with CPR distances greater than 10 mm need not be monitored unless they become symptomatic.

Results of Conserve Plus® metal-on-metal hip resurfacing for post-traumatic arthritis and osteonecrosis.

The safety and efficacy of metal-on-metal surface arthroplasty in post-traumatic arthritis and post-traumatic osteonecrosis (PT OA and PT ON) cases has not previously been thoroughly investigated. This study compared the outcomes of metal-on-metal hip resurfacing (HR) in patients performed for an indication of OA secondary to trauma to compared to PT ON. Metal-on-metal resurfacing arthroplasties were performed on 62 hips, 43 with PT OA and 19 with PT ON with secondary osteoarthritis. There were 51 males and 11 females. All patients were followed up clinically and radiographically with a mean follow-up of 87.2 months. Clinical outcome scores, survivorship, and radiographs were compared between the PT OA and PT ON group. The clinical outcomes for the PT ON and PT OA groups were similar with a survival rate of 95% (95% CI 82.1% to 98.8%) for the PT OA group alone at 8 years and 91% for those with PT OA with ON at 8 years (95% CI 50.8%-98.7%). The Kaplan-Meier survivorship curves for the cohorts of PT OA and PT ON patients were not statistically significantly different (Log rank, p=0.6036). Metal-on-metal hip resurfacing appears to be a safe and effective procedure for the treatment of both post-traumatic osteoarthritis and osteonecrosis.